Download Practice Makes Less than Perfect Vision William J. Denton, OD

Practice Makes Less than Perfect Vision
William J. Denton, OD, FAAO
Home:
822 Acacia Dr.
Sumter, SC 29150
(803)236-7589
[email protected]
Work:
6439 Garners Ferry Rd., Optometry Clinic – 2D153
WJB Dorn VAMC
Columbia, SC 29209
[email protected]
ABSTRACT:
Introduction: A simple scarring or corneal deposit is quite common in the average person. If the scarring or deposition is
within the visual axis, it oftentimes can significantly affect the visual acuity of that eye. Case Report: This patient had
decreased vision potential in his right eye due to lead poisoning. The cause was from an excessive amount of shooting
practice while in the military without wearing eye protection. Conclusion: The patient ended up regaining his vision once
again after being successfully fitted with a scleral lens thirty years later.
Key Words: Lead, Toxicity, Scleral Lenses, Corneal Distortion
INTRODUCTION:
A wide variety of metals1 and substances2 have been proven to cause toxic effects of the cornea. At times
disease progression can cause an accumulation that causes coloration or scarring, like a Fleisher ring in
keratoconus. Some drug toxic effects do not affect visual acuity despite a significant presence on the
cornea. An example of this is the vortex keratopathy seen after using amiodarone. Much depends on the
severity of the causing agent what quantity of the vision is affected.
CASE REPORT:
KT is a 63 year-old Caucasian veteran presenting to the contact lens clinic to improve his blurred vision
in his OD. He was referred from our disease clinic where he had an ocular health examination including a
dilated eye examination.
Systemic diseases/complications and modes of treatment:
Problem List
Methicillin Resistant Staphylococcus Aureus
Amputation of right lower limb below the knee
History of cellulitis
Medication/Device
Methadone
Diabetes (since 2006)
Erectile Dysfunction
Gout
Hypertension
Hyperlipidemia
Diabetic neuropathy
Sleep apnea
Restless legs syndrome
Insomnia
Depression
Metformin
Sildenafil
Colchicine
Timolol
Atorvastatin
Diazepam
CPAP machine
Pramipexole
dihydrochloride
Zolpidem
tartrate/Modafinil
Duloxetine
First Exam:
KT stated his OD was blurred from “lead poisoning from shooting 1500 rounds a day for most of 3 years”
from 1980 to 1983 while in t he military. His anterior segment appeared unremarkable, except for his OD
cornea. It had peripheral opacification that was greatest inferiorly and nasally. OS cornea was normal.
His entering visual acuity with his habitual glasses was OD: 20/100 and OS: 20/25+2
Habitual glasses prescription:
OD: Plano DS
OS: +0.50-0.75x100 +2.25 PAL
Subjective glasses prescription:
OD: -1.00-1.25x090
OS: Plano-0.75x115 +2.25 PAL
Best corrected visual acuity (BCVA) with glasses:
OD: 20/70
OS: 20/25+2
Keratometry (K) readings were:
OD: 46.12@180; <36.00@090
OS: 40.62@180; 41.00@090
When evaluating him to determine if he would be a successful contact lens patient, he showed
determination and desire. KT admitted that he had blurred vision when his blood glucose was fluctuating.
He also admitted having diabetic neuropathy, but that his wife would be willing to put the lens in his eye
before she went to work in the morning. KT stated that the reason for his last rigid gas permeable (RGP)
contact not working was due to extreme discomfort. Even with some reluctance, a trial scleral contact
lens was placed on his OD with fluorescein strips coloring the fluid. The patient instantly was impressed
with both the comfort and the visual acuity. The lens was allowed to settle thirty minutes.
Initial Trial:
OD:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter: 15.6
Base Curve: 8.44
Power: -1.50 D
Assessment:
*No blanching,
*Approx. .5mm, or one corneal thickness, corneal vault centrally
*No corneal touch was observed
Subjective: Good comfort; good vision
Over-refraction: +0.75 D 20/20First Order:
The lens was ordered and KT was informed he would receive a telephone call when the lens arrived to
make an appointment. He was also reminded to bring his wife as she would need to be shown how to
insert and remove, since this lens inserts differently than his past RGP lens.
Second Visit:
The patient arrived at the next appointment without his wife. There was some misunderstanding;
however, he needed to come to the VA medical center anyways due to a follow-up to a recent fall and
hospitalization. KT appeared pretty weak and still recovering from his fall. He had significant risks for a
fall with a lower limb amputation and decreased stereopsis from his decreased vision OD. It is believed
that his stereopsis would improve with this scleral lens and his tendency to fall may reduce.
Third Visit:
At his next follow-up appointment, his wife was able to also attend. The patient apparently did not
communicate to his wife that this type of lens is inserted differently than his last RGP. The lens was
inserted without fluorescein coloring and allowed to settle for approximately thirty minutes.
OD:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter: 15.6
Base Curve: 8.44
Power: -0.75D
Assessment:
*No blanching,
*Approx. 0.5mm, or one corneal thickness, corneal vault centrally.
*No corneal touch was observed.
Subjective: Good comfort; good vision
Over-refraction: Plano 20/20-
The assessment was the same as the last exam with 20/20- visual acuity. KT was very impressed and
looked forward to visiting the shooting range that week. His wife had no difficulty inserting the lens or
removing it. A peroxide based cleaning system was also shown with proper instructions and was learned
quite easily.
Follow-Up Phone Call:
Due to the distance the patient lived from the medical center, he was called approximately three months
later. He admitted wearing the lens 5-6 days out of the week with continued improved vision with
wearing time of 12 or more hours a day and never sleeping with it in. He did notice his vision in both
eyes reduces occasionally when his blood glucose levels fluctuate significantly. This was seen as normal
for him.
Discussion:
It would be easy to assume this patient wouldn’t be willing to be fit for a scleral lens or that he wouldn’t
be a good candidate because of his diabetic neuropathy that prevents him from inserting his own lens.
This is a great example of how a willing individual places an importance on improving his vision as long
as it feels comfortable. He also is dependent on his wife for successful insertion and removal. If his wife
was not willing or capable to assist in his venue, he would not be the topic of this case report. It is
important to gauge a patient’s interest despite disability, age or prior experiences. It is furthermore
important to instigate as to what other modes of assistance are available to each patient.
Fluctuating visual acuity from unstable blood glucose control can be a significant reason not to prescribe
lenses. This patient was an experienced diabetic and knew the cause, effect and expectations of his vision
while constantly fighting the blood glucose tug-of-war.
Conclusion:
Corneal scarring or deposition is quite common in even the average person. If significant enough and
within the visual axis it can significantly decrease the visual acuity in that eye. This case report discusses
a patient who had decreased vision potential OD due to lead poisoning from extensive training at a
shooting range without eye protection. The patient ended up regaining his vision once again after being
successfully fitted with a scleral lens thirty years later.
REFERENCES:
1. Schlötzer-Schrehardt U, Holbach LM, Hofmann-Rummelt C, Naumann GO. Multifocal
corneal argyrosis after an explosion injury. Cornea. 2001 Jul;20(5):553-557.
2. Hollander DA, Aldave AJ. Drug-induced corneal complications. Curr Opin Ophthalmol.
2004 Dec;15(6):541-548.